PHYSICS FINAL EXAM NOTES: 2006
Last chance for Q4 work. Get course evaluation to start??? (another 2 pts on final!)
Group Part:
Wed or Thur June 7/8 2006
Group Section: How is Physics used in everyday life? Essay/Reaction… 10 pts on final
List of physics topics and how they can be applied in real life, and how they can be used in
helping make societal decisions
Fri: Group Section of Exam: (15% of final)
Academic: Work in Groups of 2 or 3. Match scenes from 18 minutes of cartoons with physics principles.
Describe 5-7 scenes and the physics principles involved, and sample measurements that could be made. Turn in
class or at exam.
Honors: Work in Groups of 2. Match scenes from 18 minutes of cartoons with physics principles (from entire
year). Describe 7 scenes and the physics principles involved, and sample measurements that could be made. Turn
in class or Monday.
Mon Shortened 20 minute classes for review, finishing of cartoon exam, evaluation
FINAL EXAM: (BRING BOOK, CALCULATOR, PENCIL, GroupExam (2 parts) etc..)
Per 2 Tue,10:10-12:15 , Per 3 Wed,7:45-9:50
83 multiple choice questions (3-4 problems), 3 essays, 2 word problem (6 parts). Most questions taken from old
tests.
Per 4 Wed 10:10-12:15 , Per 5 Thur,7:45-9:50, Per 6 Thu,r 10:10-12:15 83 multiple choice questions (3-4
problems),, 3 essays, 3 word problems. Most questions taken from old tests.
CONCEPTS ON EXAM itself:
Energy units
Energy Types
Energy transformations
Work/Kinetic/Potential Energy
Mechanical Advantage/Machines
Chap 5
Phase Changes and Heat
Kinetic Molecular Theory
Heat and Temperature
Specific Heat
Pressure
Bernoulli’s Principle/Flight
Adiabatic Cooling
Simple Harmonic Motion
Wave Properties
Sound Wave Properties
Speed of Sound
Doppler Effect
Standing Waves
Overtones/Harmonics
Chap 7
Circular Motion Forces
Centripetal Acceleration
Linear Velocity
Chap 10
Chap 11
Chap 9
Chap 12
Chap 13
EXAMPLES OF ESSAY QUESTIONS AND WORD PROBLEMS FROM SEMESTER TWO TESTS:
Imagine coal burning in a power plant, which heats up water, to create steam to turn a turbine, to turn a coil of
wire near a magnet, which generates electricity, which travels to your house. You drive home, press a battery
operated infrared remote, which causes the garage door motor to turn, which lifts up the garage door,
compressing the spring.List all the possible energy changes from start to finish in this device, and identify where
energy might be lost along the way. Sketch a diagram if you need to.
------------A ball is pulled back on a elastic string 5 cm (=.05 m)with 10 Newtons of force. If there is no friction, and the
ball has a mass of 2 kg, how high will it go?
---If you use a machine to increase output force, what factor would have to be sacrificed? Give an example?
----A girl pushes a box that has a mass of 65 kg up an incline. If the girl exerts a force of
150 N along the incline, what is the mechanical advantage of the incline?
-----A force of 1250 N is needed to move a crate weighing 3470 N up a ramp that is 5.21 m
long. If the elevated end of the ramp is 0.750 m high, what is the efficiency of the ramp?
-----There is a compound machine that has a person pulling up a three string pulley, which pulls up a 2:1 lever, which
pulls down a string, which pulls up a weight moving up a ramp.
Sketch this:
Explain/show how you would get the ideal mechanical advantage of this compund machine.
Explain where mechanical energy might be lost.
Use this as an example to explain why we should or shouldn't use complex machines to do simple tasks.
---------A bouncy ball is dropped towards the earth... How is energy conserved: on the way down, when it hits, and
after it bounces up? Sketch a graph of what the three types of energy would look like over time.
--------------A still person with a mass of 140 kilogram catches a 10 kilogram ball going 20 meters/second, which causes
him to roll down a hill that is 3 meters high holding the ball at 1.5 m/s What is the total energy before the
collision?What is the total energy after the collision?
-----If they are on the top of a 3 meter tall hill, what is the velocity at the bottom of the hill?
Explain why you might want to wire your house using parallel circuits, not series.
---What is the end result of the second law of thermodynamics if the whole universe is one connected system?
Explain
---A flat container holds 200 g of water. Over a 10 min period, 1.5 g of water evaporates
from the surface. What is the approximate temperature change of the remaining 198.5 g of water?
----If 4 kilograms of -2 degree ice are dropped from 50, 000 meters, hits the ground and changes entirely to water,
what is the final temperature of the water?
---4 grams of aluminum at 50 degrees Celsius, with a specific heat of 900 are mixed with 20 grams of water at 32
degrees Celsius. Calculate the equilibrium temperature.
-----A 12 Volt battery is set in a circuit in parallel with a 40 ohm and 30 ohm resistor, then to a light bulb. Draw a
picture of the working circuit. Calculate the current and power through the bulb.
------A pitcher of iced tea is made by adding ice to 1.8 kg of hot tea (water) with an initial temperature
of 80.0°C. How many kilograms of ice, which has an initial temperature of -1.0°C, are
required to bring the mixture to 10.0°C?
---------------How much faster does the air on top of a 50 kg glider that has a surface area of 20 meters squared have to move
in order to lift it? What are the four forces acting on it? What does the force of lift have to be at least equal to?
What pressure difference is this? What velocity difference (for air) is this?
--Explain how Bernoulli’s principle can be thought of as restating conservation of energy
---I make a sound at a frequency of 500 Hz and note that the echo returns to me 10 seconds later from a wall 1500
meters away. What is the wavelength of the sound?
---Explain with word, pictures, math.... how an object moving around a circle is an example of simple harmonic
motion and could create a wave. Make certain to label your drawing.
----If you slosh the water back and forth in a bathtub at the correct frequency, the water rises first at one end and
then at the other. Suppose you can make a standing wave in a 150-cm-long tub with a frequency of 0.30 Hz.
Draw this (hint, label the crest, equilibrium and trough), then answer What is the velocity of the water wave?
---------------A Physics teacher swings a cup of water around his head with a 4 meter long string.
What is the centripetal acceleration needed to make sure that the water doesn’t fall out?
What is the minimum speed at which he must swing it?
What is the period of his swing?
--------------------A tuning fork with a frequency of 400 Hz is held above an CLOSED PIPE air column. If the air temperature is
15 degree C, what is the wavelength & frequency of the fundamental and the first harmonic overtone note? Draw
a picture of the waves in the pipe, then sketch how they would appear together (the resultant waveform).
___________________
**If a train 50 meters makes a 1000 Hz whistle (closed pipe) with 31.4 Watts of power, and is coming towards
you at 80 m/s….
What is the note that you hear, and how loud is it? (Show work!!!)
_________________________________________________
How can beats and resonance be used to find out if a guitar is in tune?
_________________________________________________
Describe how air vibrating makes musical sound waves in an instrument like a trumpet. Be sure to use wave
vocabulary words such as resonance, harmonics, etc…
PHYSICS FINAL EXAM
D= ViT + 1/2 AT2
Vf2= Vi2 + 2AD
Formula Sheet, pg 1 of 4
A=∆V
∆T
F= mA
ENERGY
Power in Watts = Work/Time
Work (Joules)= Force (N) * Distance (m)= ∆ Mechanical Energy
KE= 1/2*M* V^2
KE= Kinetic Energy in Joules
PE= M*g*h, g= 9.8 m/sec^2 or Weight (N)= Force of Gravity= mg
PE =Potential Energy in Joules
or PE = 1/2*K*x^2 for a spring,
Force(N) =kx (x in meters pulled back from equilibrium
CONSERVATION OF ENERGY:
∆E =∆E
KE + EPE + PE + Q (heat) + Work stays constant
--------------------------------------------------------------------------MACHINES:
Actual Mechanical Advantage always=
Resistance Force out
Effort Force in
Ideal Mechanical Advantage=
Dist of Effort
Dist of Resistance
for lever:IMA= effort arm/resis arm pulley IMA=#strings up,
ramp IMA= length/height, wheel IMA= wheel/axle
Efficiency = AMA/IMA or Work out /Work In
-----------------------------------------------------
ELECTRICITY:
Power (Watts) = Energy (Joules)/Time (sec)
Power(Watts) = Current(Amps) * Voltage (Volts)
Voltage (Volts) = Current (Amps) * Resistance (Ohms)
Voltage (Volts) = Energy (Joules)/Charge (Coulombs)
-1 Coulomb of Charge = 6.2 * 1018 electrons
Electric Force is proportional to Charges/Dis2
Electric Field is Force/Charge
Series Circuits: Rtot = R1 + R2 …..
Parallel Circuits: V1=V2, 1/Rtot = 1/R1 + 1/R2 ……
---------D= ViT + 1/2 AT2
Vf2= Vi2 + 2AD
A=∆V /∆T
-------------------------------------------CONSERVATION OF ENERGY:
∆Q + KE + PE
+ ∆W =
∆Q + KE + PE
+ ∆W
KE= ½ M V2
KE= Kinetic Energy in Joules
GPE= M*g*h, g= 9.8 m/sec2
PE =Potential Energy in Joules
EPE = ½ k x2
k is spring constant k=F/x
•∆Work (Joules)= Force (N) * ∆Distance (m) = Pressure (Pa) * ∆ Volume
(meters cubed)
HEAT ∆Q
Two substances in contact: ∆Q=∆Q for thermal equilibrium
-Increasing/decreasing temperature without changing phase:
(C is the specific heat of a substance changing temperature)
∆Q=m*C*∆T
-Changing phase:
∆Q=m*Hf for melting/freezing,
∆Q=m*Hv for vaporizing/condensing
(Hf and Hv are the heat of fusion and the heat of vaporization for a
substance changing phase)
Thermodynamics Law 1 Conservation of Energy
Heat Added = Internal Energy(Temp)
+ Work done
∆Q
=
∆U
+ ∆Work
Efficiency = (Thot-Tcold)/Thot (law 2)
T=Temperature in Kelvin
Entropy or Order to Chaos, 2nd law
WATER: ICE:
°K
WATER:
C=2090 J/Kg °K,
Liquid C=4187 J/Kg °K,
Hf=335, 000 J/kg
STEAM
C=2020 J/Kg
Hv=2,260,000 J/Kg
Person:
C= 3470 J/Kg °K, C for liquid or gas person=1674 J/Kg °K
boils at 1700 degrees Celsius
Hf=277633 J/Kg, Hv=1872988 J/Kg,
Other conversions:
Density of Water= 1 gram per milliliter=1000 kilograms per cubic meter
1000 grams= 1 kilogram, 1 kilogram=.001 grams
degrees Celsius= degrees Kelvin- 273
1 Kilocalorie= 1 Calorie = 1000 calories = 4187 Joules
1 Kilowatt Hour = 861 Calories
PRESSURE
water has the density of 1 gram per ml, 1 Kg per Liter, 1000 kg per cubic meter
Normal sea level pressure is 101,300 Pascals (SI Unit)or
101.3 kiloPascals, or
101,300 Newtons per square meter...
also,
1 atmosphere,
14.7 pounds per square inch,
998 Torr,
o) 998 millibars,
29.2 inches of mercury,
10.3 meters of water, etc...
Weight (submerged)= Weight - Weight of Fluid Displaced (Archimedes)
V= 1 cubic meter= 1000 Liters = 1,000,000 cubic centimeters
A=1 square meter = 10000 square centimeters
M=1 kilogram = 1000 grams
Volume = Area times Distance
F net =Weight (submerged)= Weight - Weight of Fluid Displaced (Archimedes)
= Dens (Vol) - Dens(fluid)*Volume (fluid)
W=Weight (N)=Mass(Kg) times g
F=(Force = Mass times Acceleration) (Newton)
D= Density = Mass (kg)/Volume (cubic meters), D=M/V, in kg/m3
Mass = Density times Volume, M=DV
Volume=Mass /Density, or V=M/D
Pressure (Pa) = Force (N)/ Area (square meters) , P=F/A
Force (N) = Pressure (Pa) times Area (square meters) F=PA
Pressure is constant in a static fluid (Pascal) F1 /A1 = F2/A2
for flowing fluids, rate of flow (Volume/time) is constant so that
velocity(m/s) times Area (square meters) = velocity (m/s) times Area
vA=vA
Pressure(Pa) + 1/2* Density *(velocity squared) + Density* g *height is same as
conservation of energy (times volume) , or Bernoulli’s equation for fluids,
P + 1/2D (v)2 + Dgh = P + 1/2D(v)2 + Dgh (Bernoulli)
(For no motion, P=P1 + Dgh, For no height change, and starting from 0 speed,
P=P+.5Dv2, )
Simple Harmonic Oscillators/Motion
and Angular/Circular Motion /Waves/SOUND
T  2 
Pendulum Period=
T  2 
L
g
L=Length in meters
m
k
Spring: Period=
where k is the spring constant k= Force/distance,
m=mass inKg, k=spring constant
WAVES:
 Period T =1/ƒ
V=D/T=f*WL
v = f * WL for any wave
Period= T= Seconds per Wave or Seconds per Revolution
WAVES/Circular Motion
Period=T=1/ƒ
V=ƒ WL for any wave, or V=ƒ/T
ƒ is frequency in waves/sec or Hertz, WL is wavelength in meters
or
ƒ is frequency in revolutions/sec or Hertz, WL is circumference=2pi r in meters
V= Linear Velocity in meters per second, or V=2pi r/T, V=ƒ 2 pi r
V=w/r , w is angular velocity in radians per sec (360°=2pi radians)
C=WL=2pi r
Centripetal Acceleration A=V2/r
Sound
WAVES: Period=1/ƒ
V=ƒ *WL for any wave
Sound Open Pipe WL=2 L
ƒ, 2ƒ, 3ƒ, etc.
Closed Pipe WL=4 L ƒ, 3ƒ, 5ƒ etc...
Standing Waves ƒ = nV/ 2L for strings, open pipes (n = number of antinodes) n=1 is
the fundamental
ƒ = nV/ 4L for closed pipes (n = number of antinodes)
Beats: ƒ=ƒ1-ƒ2
V=331 m/s + .6 * Temp for Sound
Doppler Shift f=f0 (Vsnd + Vdetector)/(Vsnd-Vsrce)
10-12 Watts/m2 = 0 decibels
10-11 Watts/m2 = 10 decibels = twice as loud
Intensity = Power/Area ( Area of a sphere = 4πr2 )